The overall objective of this research is to elucidate the molecular processes involved in biosynthesis and assembly of fibrinogen. Fibrinogen is composed of three pairs of nonidentical polypeptide chains which are held together through a complex set of disulfide bonds. Experiments are being carried out to determine if each polypeptide chain subunit is made from an individual template RNA's or whether all three polypeptides are synthesized from a single mRNA. Studies are also ongoing to isolate and characterize the template RNA of fibrinogen. It is well known that fibrinogen as well as otheR hepatically derived proteins are stimulated following certain types of trauma. We are investigating what factor or factors are involved in eliciting this increased synthesis of fibrinogen. These experiments should provide detailed information on the control of fibrinogen synthesis. Since fibrinogen has a major role in hemostasis and since the concentration of fibrinogen has a unique influence on the viscosity of plasma, basic knowledge about control of its synthesis and release are pertinent to cardiovascular research and treatment of cardiovascular disorders. BIBLIOGRAPHIC REFERENCES: Bouma, Hessel III, G.M. Fuller. Partial Chemical Characterization of Rat Fibrinogen. J. Biol. Chem. 250:4678, 1975. Bouma, Hessel, III, Sau-Wah Kwan, and Gerald M. Fuller. Radioimmunological Identification of Polysomes Synthesizing Fibrinogen Polypeptide Chains. Biochemistry. (In press).